Structure, Physicochemical Properties, and In Vitro Digestibility of Heat‐Moisture Treatment Lotus Root Starch and Its Application in Sweet Potato Starch Noodles

ABSTRACT This study investigated the effect of heat moisture treatment (HMT) on the structure, physicochemical properties, and in vitro digestibility of lotus root starch (LRS). The application of HMT‐modified LRS in sweet potato starch noodles (SPSNs) was also evaluated. Results showed that HMT‐modified LRS exhibited a rougher surface with some pits. HMT did not alter the B‐type crystalline pattern, but it significantly increased the relative crystallinity of LRS (crystallinity: 12.25–43.04). The short‐range order of LRS (R 1047/1022 :1.99–4.17, R 998/1022 : 7.23–11.05) was enhanced by HMT. HMT treatment resulted in an increase in gelatinization temperature and enthalpy, as well as water and oil absorption capacities, and pasting temperatures and viscosity of LRS, while reducing swelling power and solubility. Meanwhile, HMT‐modified LRS demonstrated lower G' and G″ values with tanδ<1. The resistant starch (RS) content decreased after HMT treatment, but had no impact on the total content of slowly digestible starch (SDS) and RS. Furthermore, when incorporating HMT‐modified LRS into SPSNs, these noodles displayed lower cooking loss, shorter cooking time, higher swelling index, and softer texture. Therefore, HMT‐modified LRS can be effectively utilized as a texture‐improving agent for SPSNs targeting elderly consumers.